如何创建递归函数以创建最终数组？

Question

This problem just slapped my face that I wasn't a great developer as much as I thought I was :) I cannot figure it out how to solve it. I'm assuming there should be a recursive function to do this but I'm open to any ideas.

Basically I have an array which is generated from user input.

$answers = [
  'city' => ["Los Angeles", "San Diego", "Hollywood"],  
  'make' => ["Ferrari", "Bugatti", "Lamborghini"],
];

And another array that's associated with "city" and "make" answers.

$template = [
    ["Campaign L", "Best [make] in [city]", "Active"],
    ["Campaign O", "Cheap [make] in [city]", "Pause"],
    ["Campaign V", "Top [make] in [city]", "Active"],
    ["Campaign E", "[make] [city]", "Pause"],
    ["Campaign C", "Buy Now [make] in [city]", "Active"],
    ["Campaign A", "Sale [make] [city]", "Active"],
    ["Campaign R", "Fast [make] in [city]", "Active"],
    ["Campaign S", "Red [make] [city]", "Active"],
];

What I'm trying to do is to create a final output where I replace each answers in the template and generate a main output. I have a function to replace the tags so I'm not worried about that part however I cannot figure out how to loop through each combination.

There should be combination of each city and make so my final output should be like this:

$finalOutput = [
    ["Campaign L", "Best Ferarri in Los Angeles", "Active"],
    ["Campaign O", "Cheap Ferarri in Los Angeles", "Pause"],
    ["Campaign V", "Top Ferarri in Los Angeles", "Active"],
    ["Campaign E", "Ferarri Los Angeles", "Pause"],
    ["Campaign C", "Buy Now Ferarri in Los Angeles", "Active"],
    ["Campaign A", "Sale Ferarri Los Angeles", "Active"],
    ["Campaign R", "Fast Ferarri in Los Angeles", "Active"],
    ["Campaign S", "Red Ferarri Los Angeles", "Active"],
    ["Campaign L", "Best Bugatti in Los Angeles", "Active"],
    ["Campaign O", "Cheap Bugatti in Los Angeles", "Pause"],
    ["Campaign V", "Top Bugatti in Los Angeles", "Active"],
    ["Campaign E", "Bugatti Los Angeles", "Pause"],
    ["Campaign C", "Buy Now Bugatti in Los Angeles", "Active"],
    ["Campaign A", "Sale Bugatti Los Angeles", "Active"],
    ["Campaign R", "Fast Bugatti in Los Angeles", "Active"],
    ["Campaign S", "Red Bugatti Los Angeles", "Active"],
    ...
    ...
    ...
    ...
   and goes on with other combinations...
];

I'm looking for a solution where it should also work when there are three items in the answer array (ex: [make] [model] [city]). How can I achieve this? Any ideas appreciated!

Thanks

Answer 1

Here's a corrected version. A little sloppy, was just going for the quickest solution, but it should give you a place to start.

foreach($template as $fields => $rows) {

    $fields = explode(' ', $fields);

    foreach($fields as $i => $field) {
        $replacements[$i] = $answers[$field];
    }

    $first_answers = array_shift($replacements);
    $first_field   = array_shift($fields);

    for($i = 0; $i < count($first_answers); $i++) {
        foreach($replacements as $j => $values) {
            foreach($values as $replacement) {
                foreach($rows as $row) {
                    $new_row = [];
                    foreach($row as $col => $text) {
                        $text = str_replace('['.$first_field.']', $first_answers[$i], $text);
                        $text = str_replace('['.$fields[$j].']', $replacement, $text);
                        $new_row[] = $text;
                    }
                    $finalOutput[] = $new_row;
                }
            }
        }
    }
}